Our app has been stuck in Amazon's release process for two weeks. They have not yet approved it for use with HD devices (like their tablets), and the only response we get to multiple emails asking for information is a cut-and-paste reply. It appears the same thing has happened to a number of other developers, who are stuck - like we are - waiting for approval.

In the meantime, you can follow these steps to install the app on a Kindle Fire HD or Kindle Fire HDX (and it works just fine):